Patent GB-250463-A (GB)
Title: Improvements in multicolour printing presses
IPC: B41F21/08
Filed: 1925-09-09
Abstract: 250,463. White, M. L. Sept. 9, 1925. Delivery apparatus; grippers and gripper mechanism. - A rotary multi-colour printing. machine is constructed so as to be, capable of printing sheets in four colours, or to print double the number of sheets in two colours. The sheets can .be fed from one pile, or from two piles, and may be delivered in one pile, or alternate sheets may be delivered in separate piles. The sheets are fed from piles 22, 24, Fig. 1, by automatic feeders 21, 23, and are fed by cylinders 17, 18 to grippers 19 on gripper shafts 33, carried by a rotary carrier 20 which passes between two printing-couples 11 - - 14. The sheets are delivered by chains 25 with grippers 26 which can deposit the printed sheets on either of two piles 27, 28, or alternately on the two piles. When it is desired to inspect a printed sheet, the delivery apparatus can be arranged to deposit a sheet on a plate in a recess 85, and this sheet can be removed by hand. For printing sheets in four colours, the sheets are fed from the pile 24, and cylinder 17, and as each sheet is carried around by the carrier 20 for nearly two revolutions, the sheets are fed to alternate grippers 19. The carrier 20 is fitted with five sets of grippers so that as the printed sheet is carried for a. second time past the printing-couples, it is printed on by different plates carried by the cyilnders 11, 13. For printing sheets in two colours the feed cylinder 18 is put into action and each cylinder 17, 18 feeds a sheet to alternate grippers, and these sheets are delivered in succession by the delivery grippers 26. To convert the machine from a four-colour to a two-colour machine a common control mechanism is provided to vary the action of the feeding and delivery grippers and to throw the cylinder 18 out of action for four-colour work. This control mechanism comprises a hand-wheel on a shaft 50, Fig. 2, which is threaded to engage a nut on a yoke which is adapted to cause the driving-gear of the cylinder 18 to be put out of gear, and also a cam 36 for opening the grippers 19 is simultaneously moved laterally out of the path of bowls 35 on the arms of the gripper shafts. The shaft 50 is connected by sprocket gearing 80, 81, Fig. 8, to other screws for operating the cams of the gripper devices. The delivery grippers 26, Figs. 2 and 14, on roller chains 25 pass over rollers 42, 43, 120, of which the rollers 43 are driven by gearing from the impression cylinder 14. The gripping members 63 are normally spring-closed, but are opened to receive the sheets by a cam 72 acting on bowls 70, 71 on lever arms connected to the grippers 63. The alternate grippers are fitted with bowls 70, 71, Fig. 8, of different widths, and the acting surface 74 of the cam 72 is laterally adjustable by a screwed shaft 78 operated by the common control mechanism. The cam surface 74 may be set as shown in Fig. 8 for two-colour printing, and in this case all the grippers 63 are opened to receive sheets from the grippers 19. The cam can, however, be moved to the right, Fig. 8, in which case the wide bowls 71 are prevented by the edge 73 from moving into the recess 74, and only alternate sheets are received by the grippers. If it is desired to deposit a sheet for inspection on the plate 85, a cam plate is depressed by a handlever to open the grippers when at the righthand edge of the plate 85. The sheets are normally delivered to piles 27 or 28, the grippers 26 being opened to deposit the sheets by means of a fixed cam 137, Fig. 15, which causes the sheet to be delivered to the pile 28 if it has not already been released by a pivoted cam which causes it to be delivered to the pile 27. The setting of this cam is controlled by a lever-andlink connection from a shaft 105 which is oscillated by a variable cam mechanism adapted to permit the sheets to be delivered all to the pile 28, or all to the pile 27, or to be delivered alternately to the two piles when set for two-colour printing, or when set for four-colour printing. The variable cam mechanism comprises a cam 116, Figs. 14, 18, and 20, with which engages a roller 114 on a spring-pressed arm 108 carried by a shaft 112 which is splined to bearings in the frames 88, and is laterally adjustable by a bell-crank lever 127, Fig. 18, operable by a rod 130 formed with recesses 130<a>, which are spring- pressed to engage a fixed catch 130<b> to hold the shaft 112 in one of four set positions. The cam 116 has four different operative surfaces which are offset laterally with respect to one another by a distance approximately equal to the width of the roller 114, and the roller 114 can be set to engage either one of the four surfaces. One form of cam-surface is shown in section in Fig. 20, and serves to cause the sheets to be delivered alternately into the piles 27, 28 when the machine is printing in two colours. A similar cam-surface with only one protuberance engages the roller 114 for alternate delivery when printing in four colours. The other two surfaces of the cam are circular in cross-section, the larger circle being of the same radius as the protuberances, and the smaller one of the same radius as the plane portion of the cam shown in Fig. 20. When the sheets are delivered to the pile 28, the opening above the pile 27 is adapted to be covered by a series of guides carried by a parallel link arrangement operated from the shaft 105 which controls the cam for opening the grippers to deposit the sheet on the pile 27. These guides are raised above the sheet when it is to be deposited on the pile 27.